Simple Workflow Access Protocol (SWAP) Keith Swenson July 14, 1998

Overview n Workflow u Requirements n Design Details n Relationship to: u WfMC standards u Event Notification

Workflow Management Coalition n Started in ‘93 n Organization of over 200 vendors, users, analysts n Purpose is to u Educate the market on workflow u Develop interoperability standards n Based on a workflow architecture n

The Nature of Workflow n A model of a business process n Every organization is different n Aggregate organizational behavior is not predictable n Effect on Design: u Customized for End User u Islands of Automation

Workflow == Integration n Workflow is an integrating technology u different people u different tasks u different tools u different places u together in one process

Service: Black Box n There is a service “out there” which takes a long time to complete n We want to configure a program “here” to call the service. n How much does the program “here” have to be given about the service “there” in order to start it, monitor it, control it, and be notified when it is completed?

Two Other Standards n jFlow - OMG technology u requires CORBA u requires Business Objects (BOCA) u firewall problems (domains of authority) n WfMC IF4 / MIME u unreliable overhead u unpredictable delays u error handling is complex

SWAP Problem Statement A standard protocol is needed to integrate work providers, asynchronous services, across the intranet/internet and provide for their interaction. The integration and interactions consist of control and monitoring of the work. Control means creating the work, setting up the work, starting the work, stopping the work, being informed of exceptions, being informed of the completion of the work and getting the results of the work Monitoring means checking on the current status of the work and getting a history of the execution of the work. The protocol should be light weight and easy to implement, so that a variety of devices and situations can be covered.

Basic Interaction n Start with URI of the ProcessDefinition Invoke the createProcessInstance command, get the URI of ProcessInstance Invoke the createProcessInstance command, get the URI of ProcessInstance n Give the URI of the Observer to the ProcessInstance When done, the ProcessInstance invokes the completed command on the Observer. When done, the ProcessInstance invokes the completed command on the Observer.

Observer / Service Model Process Definition ObserverProcess Instance Start Pause Resume Check Status Update Data Check Results Events Completed Results

Both Polling & Event Oriented Using the URI of the ProcessInstance, the propFind command is invoked, to retrieve current status. Using the URI of the ProcessInstance, the propFind command is invoked, to retrieve current status. u Needed when observer has no permanent web address. n When observer has an URI, then register it to receive the completion event. u Useful to avoid traffic due to polling.

Work Breakdown

Two parts to each action

Workflow Process

Hierarchical Workflow

Observer / Process Model Process Definition ObserverProcess Instance Process Definition Activity Observer Process Instsance

Organization to Organization WW HTTP Firewall

Is SWAP an Event Protocol? n Observer / Process is a Relationship u each object has some knowledge of and requirements on the other n Need for other events u achievement of a particular step in a process u a particular condition on the data values u SWAP does not handle these

SWAP != Event Notification n SWAP originally had a SUBSCRIBE / UNSUBSCRIBE methods u Because no event notification service existed n Current feeling is to pull these out and adopt whatever event standard is adopted by IETF

Lightweight Events n Remember the islands of automation? u existing workflow systems u in existing departments u workflow systems themselves are reliable u need to get them interoperating n The requirement of a separate event service is problematic

SWAP Status n n n Not yet a working group, u charter under review u requirements, scenarios, spec in progress n Concentration on demonstration of operating code n Planning meeting at IETF Chicago

Summary n Workflow u Requirements n Design Details n Relationship to: u WfMC standards u Event Notification